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Faculty of Engineering and Information Sciences - Papers: Part A

2015

Molecular

Articles 1 - 8 of 8

Full-Text Articles in Social and Behavioral Sciences

The Role Of Pyrimidine And Water As Underlying Molecular Constituents For Describing Radiation Damage In Living Tissue: A Comparative Study, Martina C. Fuss, L Ellis-Gibbings, Darryl B. Jones, M J. Brunger, Francisco Blanco, A Muñoz, Paulo Limao-Vieira, Gustavo Garcia Jan 2015

The Role Of Pyrimidine And Water As Underlying Molecular Constituents For Describing Radiation Damage In Living Tissue: A Comparative Study, Martina C. Fuss, L Ellis-Gibbings, Darryl B. Jones, M J. Brunger, Francisco Blanco, A Muñoz, Paulo Limao-Vieira, Gustavo Garcia

Faculty of Engineering and Information Sciences - Papers: Part A

Water is often used as the medium for characterizing the effects of radiation on living tissue. However, in this study, charged-particle track simulations are employed to quantify the induced physicochemical and potential biological implications when a primary ionising particle with energy 10 keV strikes a medium made up entirely of water or pyrimidine. Note that pyrimidine was chosen as the DNA/RNA bases cytosine, thymine, and uracil can be considered pyrimidine derivatives. This study aims to assess the influence of the choice of medium on the charged-particle transport, and identify how appropriate it is to use water as the default ...


Brittle Versus Ductile Behaviour Of Nanotwinned Copper: A Molecular Dynamics Study, Linqing Pei, Cheng Lu, Xing Zhao, Liang Zhang, Kuiyu Cheng, Guillaume Michal, A Kiet Tieu Jan 2015

Brittle Versus Ductile Behaviour Of Nanotwinned Copper: A Molecular Dynamics Study, Linqing Pei, Cheng Lu, Xing Zhao, Liang Zhang, Kuiyu Cheng, Guillaume Michal, A Kiet Tieu

Faculty of Engineering and Information Sciences - Papers: Part A

Nanotwinned copper (Cu) exhibits an unusual combination of ultra-high yield strength and high ductility. A brittle-to-ductile transition was previously experimentally observed in nanotwinned Cu despite Cu being an intrinsically ductile metal. However, the atomic mechanisms responsible for brittle fracture and ductile fracture in nanotwinned Cu are still not clear. In this study, molecular dynamics (MD) simulations at different temperatures have been performed to investigate the fracture behaviour of a nanotwinned Cu specimen with a single-edge-notched crack whose surface coincides with a twin boundary. Three temperature ranges are identified, indicative of distinct fracture regimes, under tensile straining perpendicular to the twin ...


Molecular Dynamics Study On The Grain Boundary Dislocation Source In Nanocrystalline Copper Under Tensile Loading, Liang Zhang, Cheng Lu, A Kiet Tieu, Linqing Pei, Xing Zhao, Kuiyu Cheng Jan 2015

Molecular Dynamics Study On The Grain Boundary Dislocation Source In Nanocrystalline Copper Under Tensile Loading, Liang Zhang, Cheng Lu, A Kiet Tieu, Linqing Pei, Xing Zhao, Kuiyu Cheng

Faculty of Engineering and Information Sciences - Papers: Part A

Grain boundary (GB) is the interface between different oriented crystals of the same material, and it can have a significant effect on the many properties of materials. When the average or entire range of grain size is reduced to less than 100 nm, the conventional plastic deformation mechanisms dominated by dislocation processes become difficult and GBmediated deformation mechanisms become increasingly important. One of the mechanisms that can play a profound role in the strength and plasticity of metallic polycrystalline materials is the heterogeneous nucleation and emission of dislocations from GB. In this study, we conducted molecular dynamics simulations to study ...


The Shear Response Of Copper Bicrystals With Σ11 Symmetric And Asymmetric Tilt Grain Boundaries By Molecular Dynamics Simulation, Liang Zhang, Cheng Lu, A Kiet Tieu, Xing Zhao, Linqing Pei Jan 2015

The Shear Response Of Copper Bicrystals With Σ11 Symmetric And Asymmetric Tilt Grain Boundaries By Molecular Dynamics Simulation, Liang Zhang, Cheng Lu, A Kiet Tieu, Xing Zhao, Linqing Pei

Faculty of Engineering and Information Sciences - Papers: Part A

Grain boundaries (GBs) are important microstructure features and can significantly affect the properties of nanocrystalline materials. Molecular dynamics simulation was carried out in this study to investigate the shear response and deformation mechanisms of symmetric and asymmetric Σ11 tilt GBs in copper bicrystals. Different deformation mechanisms were reported, depending on GB inclination angles and equilibrium GB structures, including GB migration coupled to shear deformation, GB sliding caused by local atomic shuffling, and dislocation nucleation from GB. The simulation showed that migrating Σ11(1 1 3) GB under shear can be regarded as sliding of GB dislocations and their combination along ...


Single Molecular Shuttle-Junction: Shot Noise And Decoherence, Wenxi Lai, C Zhang, Zhongshui Ma Jan 2015

Single Molecular Shuttle-Junction: Shot Noise And Decoherence, Wenxi Lai, C Zhang, Zhongshui Ma

Faculty of Engineering and Information Sciences - Papers: Part A

Single molecular shuttle-junction is one kind of nanoscale electromechanical tunneling system. In this junction, a molecular island oscillates depending on its charge occupation, and this charge dependent oscillation leads to modulation of electron tunneling through the molecular island. This paper reviews recent development on the study of current, shot noise and decoherence of electrons in the single molecular shuttle-junction. We will give detail discussions on this topic using the typical system model, the theory of fully quantum master equation and the Aharonov-Bohm interferometer.


Molecular Dynamics Simulation On Generalized Stacking Fault Energies Of Fcc Metals Under Preloading Stress, Liang Zhang, Cheng Lu, A Kiet Tieu, Xing Zhao, Linqing Pei, Guillaume Michal Jan 2015

Molecular Dynamics Simulation On Generalized Stacking Fault Energies Of Fcc Metals Under Preloading Stress, Liang Zhang, Cheng Lu, A Kiet Tieu, Xing Zhao, Linqing Pei, Guillaume Michal

Faculty of Engineering and Information Sciences - Papers: Part A

Molecular dynamics (MD) simulations are performed to investigate the effects of stress on generalized stacking fault (GSF) energy of three fcc metals (Cu, Al, and Ni). The simulation model is deformed by uniaxial tension or compression in each of [111], [11-2], and [1-10] directions, respectively, before shifting the lattice to calculate the GSF curve. Simulation results show that the values of unstable stacking fault energy (γusf), stable stacking fault energy (γsf), and unstable twin fault energy (γutf) of the three elements can change with the preloaded tensile or compressive stress in different directions. The ratio of γsf/γusf, which is ...


Novel Experimental Setup For Time-Of-Flight Mass Spectrometry Ion Detection In Collisions Of Anionic Species With Neutral Gas-Phase Molecular Targets, J C. Oller, L Ellis-Gibbings, F Ferreira Da Silva, Paulo Limao-Vieira, Gustavo Garcia Jan 2015

Novel Experimental Setup For Time-Of-Flight Mass Spectrometry Ion Detection In Collisions Of Anionic Species With Neutral Gas-Phase Molecular Targets, J C. Oller, L Ellis-Gibbings, F Ferreira Da Silva, Paulo Limao-Vieira, Gustavo Garcia

Faculty of Engineering and Information Sciences - Papers: Part A

We report a novel experimental setup for studying collision induced products resulting from the interaction of anionic beams with a neutral gas-phase molecular target. The precursor projectile was admitted into vacuum through a commercial pulsed valve, with the anionic beam produced in a hollow cathode discharge-induced plasma, and guided to the interaction region by a set of deflecting plates where it was made to interact with the target beam. Depending on the collision energy regime, negative and positive species can be formed in the collision region and ions were time-of-flight (TOF) mass-analysed. Here, we present data on O-2 precursor projectile ...


Induced Molecular Dissociations As A Radiation Damage Descriptor (Nanodosimetry), A Traore, L Ellis-Gibbings, Alexey Verkhovtsev, K Krupa, A Munoz, Fernando Blanco, Gustavo Garcia Jan 2015

Induced Molecular Dissociations As A Radiation Damage Descriptor (Nanodosimetry), A Traore, L Ellis-Gibbings, Alexey Verkhovtsev, K Krupa, A Munoz, Fernando Blanco, Gustavo Garcia

Faculty of Engineering and Information Sciences - Papers: Part A

We present a nanodosimeter software based on Monte Carlo, termed: Low Energy Particle Track Simulation. For medical applications purposes, we propose bond breakings to describe the energy deposited taking water as an example. This tool aims to improve current treatment planning approach based on absorbed dose.